(Phys.org) -- Researchers and laymen alike know that some non-Newtonian fluids tend to harden quickly upon impact. Quicksand is a good example. If a person walks quickly, they wont sink. But why this happens has been somewhat of a mystery, though many in the science community have suspected it had something to do with energy being transferred to the walls of the container. New research finds thats not the case at all. Instead, after extensive testing and experimentation Scott Waitukaitis and Heinrich Jaeger of the University of Chicago have found, as they describe in their paper published in the journal Nature, that its because the particles suspended in the liquid temporarily mash together, creating a near solid....